Do you know if you currently have 2 different subscriptions to the Disney+ channel? One through the channel provider directly and one through Roku Pay? We would recommend taking a look at your account online at my.roku.com and clicking Manage your subscription to see if you have Disney+ subscription through Roku Pay.
If you need further assistance with, please reach out to our support team directly here for your 'Account or billing' issue, here: https://support.roku.com/contactus. They will be able further assist you.